Elevator safety apparatus



2 Shee ts Sheet 2 Filed May 2, 1942 H. V. MCCORMICK ELEVATOR SAFETY APPARATUS Aug. 3, 1943.

INVENTOR K. w m H M A M. //W.B w H WITNESSES 4 Patented Aug. 3, 1943 2,326,046 I ELEVATOR. SAFETY APPARATUS Harold v. McCormick, Westfield, n.1, assignor a Westinghouse Electric Elevator Company;

Jersey City, N. 3., a corporation of Illinois Application May 2, 1942, Serial No. 4413595 12 Claims. (or. 187-f-88) My invention relates to elevator safety apparatus, and more particularly to such safety apparatus as includes gripping jaws mounted on the. bottom of the car in position to engage the elevator guide rails and stop the car when its hoisting cables break or it exceeds a predetermined down speed.

One object of my invention is to provide a safety apparatus in which the gripping jaws will be self-energizing and self-equalizing when they operate to retard the car to rest.

Another object is to provide a self-energizing safety apparatus in which a relatively light force on the governor cable will start the car retarding action and the safetyapparatus willthen complete the action.

Another object is to provide a self-energizing safety apparatus in which the forces applied by the gripping jaws on the guide rails will be equalized automatically'during their operation in stopping the car.

Another object is to provide a self-energizing safety apparatus which may be adjusted to cause the. gripping jaws togrip the guide rails with a. predetermined grippingforce when they operate to stop the car.

A further object is to provide an elevator safet-y apparatus for retarding the car to rest in case the hoisting cables break or when the car exr ceeds a predetermined down speed with its hoisting cables intact.

A still further object is to provide a safety apparatus which will operate to retard the car to rest at one rate'of deceleration when its hoist- M V ihg cab les break and at a different rateof deceleration when the car overspecds in its down direction with its hoisting cables intact.

A still further object to is provide a self-energizing safety apparatus which may be adjusted to retard the car'at. different. desired predetermined rateswhen its hoisting cables break, or when it overspeeds in its downdirection with its hoisting cables. intact.

It is also an object of my invention toprovi dc a self'energizing safety apparatus which will retard the car to rest in response to one means actuated by the breaking of the hoistingcables and in response; to another means actuated by ovcrspeeding oi the car, and means for varying the retarding lorces in accordance with-whether the car responds to the breaking of the cables or to overspeeding. r

For a better understanding of the invention, reference may be had to the drawings, in which: l

accompanying Figure 1 is a view in front elevation of 'an elevator car equipped with my improved safety apparatus, v i r Fig. 2 is a view taken on line II-II of Fig. 1, illustrating the gripping jaws and their operating apparatus as viewed looking upward to the bottom of the car, 3

Fig. 3 is aview in side elevation of the and my improved safety apparatus.

Referring more'particularly to my invention, I have illustrated an" elevator car C as disposed for operation between a pair of vertical guide rails [B' and H. 'The car is mounted in a sling l2 comprising a pair of cross channelirons l3 and M at the top, a pair of cross channel irons l5and l6 at the bottom, and a pair of vertically disposed side channel irons I! and I8 which connect the top cross channel irons and the bottom cross channel irons at their outer ends. A plurality of metal plates I9 is attached to the top cross channel irons and the side channel irons. to bracethe frame and make it rigid.- The channel irons also serve as a framefor thesaie- 'ty apparatus.

The car is suspended between the guide rails by a plurality of hoisting-cables 2| connected to aplurality of cable rods 22 which pass through a plate 23 on the underside of the top channel irons and H; A cushion spring 24 is disposed on the lower end of each cable rod between the plate 23 and end washers held in place by on cross plates 32 and 331 on the undersurfacecfthe bottom channel irons i5 and it near their outer ends in position toengage the guide rails l9 and H for 'guiding thecar'in its up and down movements. r f

In accordance with my invention, I have provided a safety device 35 mounted on the car for stopping it if its hoisting cables should'b'real; or it should exceed a predetermined speed" in the down direction. The safety device includes a pair of braking devices or'gripping jaws 36 and 31 pivotally mounted on a pin 38 having its upper-end supported in an upper plate 39 and the-lower plate 33 at one end of the channel irons 1-5 l6 underneath the car in position i when they are placed in operation, I have connected them with an equalizing mechanism comprising a pair of links 43 and 44, a pair of bell crank levers 45 and 48, a link 47, a fulcrum lever 48, a connecting rod 49, a stirrup 5i], and a resilient member such as a'compression spring 5|. The one end of the link '43. is pivotally mounted on the rear arm 53 of the jaw ll and its other end is pivotally attached to theshort arm of the bell crank lever 45 which is pivotally mounted on the rear arm 54 of the gripping jaw 40 The'long arm of the bell crank lever 45 is pivotally attached to the left-hand end of the stirrup 50.

The connecting rod 4?! is slidably supported ina projecting member 55 mounted on the channel iron l6, withits one end pivotally connected to one end of the lever 48 and its other end extending through the right-hand end of the stirrup 50.

The other end of the lever- 48 is fulcrumed on a pin :52 attached to a s'lidable bar 52a. Thecompression spring-5| is disposed on the rod 49 between the right-hand end of the stirrup and an adjusting nut .56 on the outer end oftherod..".

A'nut 43a is threaded on the screw-threaded portion of the rod 49, adjacent to the right-hand end of the stirrup This nutJprovides 'a shoulder to engage the stirrup so that the spring 59 maybe given an initial compression between the foot of the stirrup and the nut 56. The shoulder nut 49a or the nut 58 may be rotated Jon. the screw-threaded portion "of the'rod 49 to adjust the initial compression of the spring and also to adjust the amount of clearance be- 7 tween the jaws and the .rails when-they are in their normal unapplied condition; The' link 41 has its one end pivotally attached to the-lever 43 at a pointfintermediate the pin 52 andjthe rod 49 and its other end pivotally attached to the long arm of the bell crank lever 45. The lever 46- is pivotally mounted onth'e rear arm '51 of the gripping jaw 36 with its short armpivotally connected to the link 44, the otherend of which is pivotally connected to the rear, arm 58-of the gripping jaw 31. r s V The nut 5% may be rotated on the outer side of the connecting rod 49 to adjust the normal compression of the spring 5| tov control in a'predetermined manner the stopping force exerted by the gripping jaws of .the guide rails.

In order thatthe gripping jawsmay be selfenergizing the jaw 41 is, provided with a wedge member 50 and the jaw 31 with a wedge member 6!. The wedgemember 6| is slidably disposed in a recess or depression 62 in the jaw 31. The upper end of therrecess'GZ is inclined toward the guiderail in such manner that if the wedge member til is lifted until it is forced into contact with the guide rail while the car is moving downwardly, a further down movement of the car will wedge the gripping jaws against the guide rail to retard the car in its down movement. A liner 63 of a low friction material is interposed between the jaw 31 and the wedge 6| to provide a lower degree-of friction between the jaw and the wedge than will exist between the wedge and the guide rail when the jaw is operated, for the purpose of insuring that the wedge will adhere to the guide rail while the jaw structure is being expanded. A shoulder 310, at the top of the recess 62 limits the upward movement of the wedge in the jaw. A link 63a pivotally attached to the jaw 37 and the wedge 65 is provided for supporting and guiding the wedge 63 in the recess 62. The wedge 60 is mounted in the gripping jaw ll in the same manner. When both wedges engage their stop shoulders vS'ia, the jaws are expanded the maximum possible and the spring 5! is compressed a predetermined amount providing an upper limit ping conditions.

The means for operating the wedge 6i upwardly in its slot to effect the stopping of the car when it exceeds a predetermined down speed comprises a lever 65 and a governor rope 66. The lever 85 is fixed on the outer end of a shaft 8'! and its inner end is connected by a link 68 to the'lower end of the wedge 6|. The governor rope comprises a cable portion 69 and a lift rod portion it. ,The cable portion passes over a governor sheave l2 at the upper end of the hatchway (not shown) and around a tension sheave [3 at the lower end of the hatchway and is connected by a shackle 14 to the upper end of the rod iii and by a shackle to the lower end of the rod. The lift rod is pivotally connected near its lower end to the lever 65, so that an upward movement of the rod relative to the car will raise the inner end of the lever 65, thus pushing the wedge Sl' upwardly to cause it to engage the guide rail H.

JThe lift rod is slidably connected to the car by a bracket i5, oneend of which is secured to the bar 253 on top of the car and the other end of which embraces the rod 70 just below the upper shackle 74 and above a tension spring '75. When the car moves in normal operation, the bracket 15 carries the governor rope along with the car, thereby rotating the governor sheave 12.

The rotation of the governor sheave 52 serves to operate a suitable governor (not shown) which will stop the rope against further movement when the car exceeds a predetermined down speed. Inasmuch as governors of this character are old and well-known, no further description thereof will be given. If desired, further details may be secured from Patent No. 1,957,311, issued May 1, 1934, on Inertia type governor and assigned to the Westinghouse Electric Elevator Company.

If the wedge 6! becomes firmly wedged against the guide rail H in a car-stopping operation, it may be forced out of its wedged position after the car is ready to resume operation by the use of an inching bar it placed against the stirrup or fulcrum 11 in position to engage a notched bar 1'3 riveted to the right-hand end of the lever 65. The inching bar '16 may be carried on the car and used, as shown in its dotted position, when necessary. I

In this installation, the rod or bar 57 is illustrated as extending horizontally from the lever 65 to the lever 65adisposeol adjacent to the wedge -60 for operating it to retard the car if the car .is pulled down by the adjust the compression i installed without the bar 61 or the lever 65a. 7 Under such conditionatheioperation of the gripping jaws 36 and .31 when the. car is making a safety stop will, by reason of the equalizing levers, operate the gripping jaws 4n and 41 to clamp the guide rail Ill, thereby bringing the. wedge 69 into operation and causing the gripping jaws at each end of the safety device to operate effectively on the guide rails l8 and l I to stop the car. In such a case, the spring 5i will cause the forces exerted by the twopairs of gripping jaws to be equalized. It may be noted that the link 44 is made shorter than the link 43 inthe equalizing apparatus 'to compensate for the different positions at which the rod 4!! and the link 6] are attached to the lever 48, since the lever 48 rotates about a fixed fulcrum. That is, the links of the levers 43 and 44 are made such that the forces at the inner ends of thegripping jaws 31 and M are 7 identical when the apparatus is operated.

The foregoing description relates to the means for operating the safety apparatus to retard the car to a stop when itexceeds a predetermined speed in the down direction. My improvement also includes an additional means for causing the safety apparatus tobe applied immediately to retard the car when the hoisting cables break. This improvement comprises the plate 23., a lever Bill, a horizontal connecting rod 8|, a vertical connecting rod 83', a bell crank lever 84, the driving rod 52a and a resilient member such as a compression spring 92. I

The plate 23 is mounted. onfthe underside of the top channelirons l3, and M by a pair of hinges 81,

plate 23 may drop downwardly from the channel irons l3 and M. The lever 8b. is mounted on the hinged portion of the plate 23 so that its lower end will be moved. to the right when the plate 23 expansion of a spring 92. The co-nnectingro-d Bl connects the lower end of the lever 80 to the upper end of the bell crank lever 82 which is rotatably mounted by a pin 8:9 on the frame plate I9 of the car. The righthand end of the lever 82 is connected by'the rod 83 to the right-hand end of the bell crank lever 84 which is pivotally mounted by a pin. 9,9 on the bottom channel iron i5. The lowerend of the downwardly extending arm of the lever 83 is pivotally'connected to the right-hand end of, the rod 85. The left-hand endofuthe rod 85 is, sl idably supported by a projecting member 9! mounted on the side of the channel iron; 15.

The compression spring 92: is mountedon the rod 52a between the projecting member 8! and the outer left-hand end of the rod; and'is maintained in position by a nut 53, so that movement of the rod 52a to the left under the action of the spring 92 will tighten the equalizing jaws to'cause themgto grip the guidera'ils, for'the purposacf stopping the car. The nut 93 maybe rotated to of the. spring 92 to the point to secure any desired predetermined pressure.

It should be observed that the fulcrum 5,2 of the lever 48 is located atone point when the safety jaws are set by-the operation of the governor rope when the car exceeds, a predetermined down speed and that it is moved to the left to another point additionally compressing spring 5!. when the hoist ropes break. and cause the safety jaws to be placed in operation This shifting of the fulcrum point of the lever 48 provides a means forsecuring a retarding force suitable for stop so that, if th hoisting cables 2 I' break, the upward force they exert will cease and the ping the oar when the'hoisting cables break and another retarding force suitable for stopping the car when it exceeds a predetermineddown speed with its hoisting cables intact.

operati n of the system V the): down movement of-the car along the gov ernor rod '10 raisesthe inner end of the lever 65 rel ive o i s. pivotal point This movement of the lever- 65 operates the link do to move the wedge member 6| upwardly in its recess 62. The rotation of the le /ch65 also rotates the .rod 61 to cause the lever 65a to raise the wedge member 69 at the other end'of; thesafety device. When the Wedge. members so and 5! move upwardly a suiii cient distance their gripping jaws to, contact the guide rails H} and l I they arewedged tightly against the guide rails by the further down movement of thecar and thereby: cause the gripping jaws to so grip the guide rails astorctard the car to rest. i

The gripping action of the two pairs of jaws is equalized because. the wedging action of the wedge members 6|, inspreading the jaws 36 and 31', causes their inner ends 51 and 53 tomove toward each other, thereby rotating th bell crank lever 46 by means of the link to exert a pull on the link 41 which moves the lever is to the right.

around its fulcrum point This movement of the lever 48 pulls the connecting rod 49 toward the right against the compression spring 5! and thus, applies a predetermined amount of force to the stirrup 50 which pulls upon the bell crank lever 45, thereby operating the link its to spread the arms 53 and 54 to. increase the gripping action of either pair of jaws will be immediateiy: transforce of the cables agar-ir mitted to-the other of javzsby means of the equalizing levers and the compression spring it is evident that the retarding effect of the gripping jaws will beequalizedat all times te the predetermined point determined by the spring 59.. It will also be evident that this predetermined point may be changed or adjusted by retating the cap nut E ato set the gripping pressure at the predetermined" degree desired.

' It. will be assumed now that thecar has been returned to serviceandjthat its hoisting cables break. The breaking of the hoisting cable re leases the operating rod fi'i'a'because the upward the plate "2' caused bythe weight of the ceases and permits the plate .to be pulled downwardly under the force i exerted by the springt i, it being evidentthat the downward movement of the plate 23 will'permitthe lever Bilandthe connecting rod 8! to 'move tothe right, thus permitting the bell crank lever E2 to rotate around "its pivot 39 to permit the vertical rod Elite move downwardly which,

in turn, permits the bell crank leverli lto rotate around its pivot 96, and thereby permit the rod 52a. to move to the left under the force of the compression spring 92. 7

The leftward movement of the rod 52a carries with it the connector 52 and the outer end of the lever 4 .5. This movement pulls the connecting rod 49 andthe link 41 closer to each other. The leftmovem'ent of the link t? operates the '49 and 4! bell crank lever 45 and-the link 44 to spreadth'e arms 57 and 56 and thereby move the jaws to and 37 intogripping position against the guide rail H. The movement'of theconnecting rod 49 to the right .pulls on the stirrup 53 through the compression spring 5|, and thereby operates sition, they carry their wedge member 6! against the guide rail'H and-a further down movement of the car wedges the wedge member 85 and the jaws 85 and 31 more tightly on the guide rail.

At the same time the downward movement of s the car causes the wedge Bil mounted on'the jaw 5| to be brought against the guide rail W,- so

that further down movement of the car wedges that wedge member more tightly between the jaws pose of retarding the car against further down movement. If the'jaws grip the guide rails with unequal forces, the equalizing mechanism will cause the gripping effect to be equalized so that the retarding effects on both sides of the carwill be ofequal value.

It will be obvious that plate 23 may be held in place by only one cable which, if broken, would apply the heavier retarding force, or by suitable cable equalizing devices the breaking of any cable could be used to apply the increased braking force.

In the apparatus illustrated, the operating rod .67 on which the levers 6'5 and 65;: are mounted will cause the wedging members 56 and 61 to be moved upwardly approximately in unison and they will be placed in operation at approximately the same time. However, in installations where the connecting rod E! is not used, the movement of the lever 43 by the compression spring 92 when the plate 23 is released will cause the gripping jaws to move toward the guide rails,.and the first wedge member to be moved into engagement with its guide rail will cause the jaws with which it is associated to griptheir guide rail, and further down movement ofthe car will so increase the gripping action that the equalizing levers will transmit the effect to the other pair of gripping jaws, thus closing them to the point where their wedge will be brought against, its 7 guide rail so that further down movement of the car will cause them to grip the guide rail'with the desired retarding effect. If the jaws grip the guide rails unequally at the'start'of'the operation, the equalizing levers will equalize the gripping action until the retarding'efle'ct of the 'two pairs of jaws is equalizedand'the value at that point will correspond to the degree of retardation for which the compression spring a! is adjusted.

. It will be apparent that the eii cctof the spring 5i or the degree of force exerted by it when the hoisting cables break will be differentfrom the force exerted by thesafety apparatus when it is operated by the governor rope when-the carexceeded its predetermined down speed withthe hoisting cables intact. by the shifting of the fulcrum point Hence it will be apparent that one predetermined degree of retarding force will be applied to the car when its safetyrdevice isoperated by the breaking of the hoisting cables and that another predetermined degree of retardingforce will be applied to the car when its safety apparatus is This diiference is secured operated by the car exceeding a predetermined down speed with its hoisting cables intact.

It will be further apparent-that these predetermined degrees of retardation may be easily adjusted by adjusting'the compression of the spring 5i by rotating the cap nut 55. It will be further evident that adjustment of the compression spring 92 by rotation of the-cap nut 93 will adjust the predetermined effect of the operating lever 33.

From the foregoing description it will be evident that I have provided a safety apparatus vhich will retard the car to rest with one degree of retardation when the hoisting cables break and with a diiferent degree of retardation when the car exceeds a predetermined down speed with its hoisting cables intact, and that I thereby prevent disagreeable or unpleasant deceleration of the car during a safety stop from whatever cause.

Although the safety apparatus has been described in connection with an elevator car, it may be used for the counterweight or any other movbody in an elevator requiring safety apparatus to prevent its falling.

Although I have illustrated and described only one specific embodiment of my invention, it is to be understood that changes therein and modifications thereof may be made without departing rom the spirit and scope of the invention.

I claim as my invention:

1. In a safety device for a body movable along a pair of guide rails by a hoisting device, a frame,

- of the body for operating the wedge members to cause the'jaws to retard the down movement of the body, a plurality of equalizing members connected to the arms of the grip-pingjaws, a fulcrum lever and a resilient member for connecting the equalizing members attached to one pair "of jaws to the equalizing members attached to the other pair of jaws whereby an opening move- 1191 t' of one pair of jaws will apply a predetermined force to close the other pair of jaws, a biasing device for biasing the fulcrum lever to operate the equalizing members to close the gripping jaws, and means responsiveto the-hoisting device remaining intact for preventing operation of the biasing device and responsive to the hoisting device breaking for releasing the biasing device to operatethe fulcrum lever to close the jaws to retard thebody.

2.- In a safety device for a body movable along a pair of guide rails by'a hoisting device, a'frame, two pairs of safety jaws, each jaw being provided with a rearwardly extending arm and one jaw of each pair being provided with a depression in its gripping face, means for pivotally mounting each pair of jaws on the frame in position to grip a guide rail, a Wedge member disposed in each of said depressions whereby down movement of the 7 car when the jaws are operated to grip the guide 7 the gripping jaws, and means responsive to the hoisting device for preventing operation of the biasing devicewhile the hoisting device remains intact and responsive to the hoisting device breaking for releasing the biasing means to operate the fulcrum lever to close the jaws to retard the body.

3. In a safety device for a body movable along a pair of guide rails by a hoisting device, a frame, two pairs of safety jaws, each jaw being provided with a rearwardly extending arm and one jaw of each pair being provided with a depression inits gripping face, means for pivotally mounting each pair of jaws on the frame in position to grip a guide rail, a wedge member disposed in each of said depressions whereby down movement of the car when the wedge members are operated wedges the jaws against the guide rails to retard the body,

means responsive to a predetermined down speed of the body for operating the wedge members to cause the jaws to grip the guide rails to retard the down movement of the body, a plurality of equalizing members connected to the arms of the gripping jaws, and a fulcrum lever and a resilient member for connecting the equalizing members of one pair of jaws to the equalizing members of the other pair of jaws whereby an opening movement of either pair of jaws will apply a predetermined force to close the other pair of jaws to equalize the retarding force applied by them.

i. In a safety device for a body movable along a pair of guide rails by a hoisting device, a frame,

two pairs of safety jaws, means for pivotally mounting each pair of the safety jaws on the frame in position to grip a guide rail, a wedge member for each pair of jaws disposed to cause the jaws to retard the down movement of the body-when they are moved into gripping engagement with guide rails, an equalizing device attached to each pair of jaws, a fulcrum lever for connecting the equalizing devices to control the actions of the jaws to equalize the forces they apply in retarding the body, means responsive to a predetermined down speed of the body to operate the wedge members to effect retardation of the body, a biasing device for biasing the fulcrum end of the fulcrum lever to operate the jaws and wedge members to retard the downward movement of the car, and means responsive to the condition of the hoisting device for restraining the biasing device from moving the fulcrum lever while the hoisting device remains intact and for releasing the biasing means to move the fulcrum lever when the hoisting device breaks.

5. In a safety device for a body movable along a pair of guide rails by a hoisting device, a frame, a plurality of safety'jaws, means for pivotally mounting the jaws on the frame in position to be moved into engagement with the guide rails, an equalizing means connecting the jaws for causing them to grip the guide rails with equal force when they are moved into engagement therewith, a resilient member mounted in the equalizing means for limiting the equalizing force to a predetermined value, means responsive to the hoisting device breaking for operating the equalizing means to effect operation of the jaws to retard the .body, and meansresponsive to a' predeter mined down speed of the body for operating the jaws to retard the down movementof the body;

6. In a safety device fora body movablealong a pair of guide rails by a hoisting device; a frame, two pairs of, safety jaws, means for pivotally mountingeach pair of jaws on the framein position for gripping a guide rail, a wedge rnember for eachpair of jaws disposed to cause the jaws to retard the down movement of the, bodywhen they are moved into gripping engagement with the guide rails,an equalizing means connecting one pair of jaws to the other for causing them to apply equal retarding forces when they are operated to retard the body, means responsive to a predetermined down speed of the body for op.- erating' the wedges to engage the rails to stop the car, and means responsive to breaking of the hoisting device for operating the equalizing means to move the jaws into engagement with the guide rails to retard the body. t

7. In a safety device for a body movable along a guide rail by a hoisting device, a frame, a pair of rail gripping jaws pivotally mounted'on the frame, one of said jaws being provided with an I angular depressionrin its rail gripping face, a

wedge member of angular shape disposed in said depression, means responsive to a predetermined down speed of the body for operating thewedge member to wedge the jaws on the guide railsto retard the down movement of the body, and a linpression in the jaw, said lining member having a' ing member disposed on the surface of the dedegree of friction sufficiently low to provide a less degree of friction between the jaw and the wedge member than the degree of friction between the wedge member and the rail. a

8. In a safety device for an elevator body movable along a guide rail by a hoisting device, a frame, a pair of rail gripping jaws pivotally mounted on the frame in position to engage the guide rail, means responsive to a predetermined down speed of the car for operating the jaws to grip the guide rail with apredetermined force to retard the body with one rate of deceleration, and means responsive of the hoisting device breaking for operating the jaws to grip the guide rail with a force different from said predetermined force to retard the body at a different rate of deceleration.

9. Ina safety device for a body movable along a pair of guide rails,,a plurality of safety jaws, means responsive to the hoisting device breaking for applying the jaws to the guide rails to retard down movement of the body with a predetermined force and means responsive to a predetermined down speed of the body for applying the jaws to the guide rails to retard' down movement of the body with a'predetermined force different from the first-named predetermined force.

10. In a safety device for a body movable along a guide rail, a frame, a pair of rail gripping jaws pivotally mounted on theframe, a wedge member mounted in the jaws,'a lever for moving the wedge member into wedging position in the jaws, a ratchet device mounted on the free end of the lever, whereby an inching bar may be used for' engaging the frame and the ratchet device to force the wedge out of its wedging position.

11. In a safety device for an elevator body movable along a guide rail by a hoisting devicaa ing efiecton the rail to retard the body, and means responsive to the hoisting device breaking for operating said braking device to apply a difierent 'predeterminedbrakinq effect on the rail to retard the body. e

12.In"a safety device for an elevator body mov able along a pair of guide rails by a hoisting device, a frame, two pairs of safety jaws pivotally mounted on the frame adjacent to the guide rails,

a plurality of equalizing levers connected to the 10 

